In the more than 40 years since automatic color photograph printers were developed, all technology has focused on the area of a given color negative as it is masked in an opaque negative carrier. As light passes through the negative in a conventional color printer, it is diffused and scattered in a chamber where red, blue and green sensors electronically read the light passing through the images of the red, blue and green layers of the film. Electronic signals activate cyan, yellow and magenta color filters of the printer simultaneously so that such filters are moved into the path of the light from a light source of the printer before the light strikes the color paper on which color positive prints are to be made. This technique is called subtractive color printing. In another method, called additive color printing, the above sequence is the same except that several electronic circuits actuate one at a time, each making a second separate exposure through the red, green and blue color filters.
Under present technology, a standard or master negative film is used as a reference against which the colors and density of an automatic printer are set and the image to be developed on the paper is compared. The standard or master negative film must be analyzed, printed and processed through color light chemistry repeatedly until, by trial and error, a good color balance is achieved. Since each trial and error step involves the printing of a photograph, such a process consumes time and materials and is relatively expensive to practice. Moreover, the degree of excellence of the color balance under present technology is contingent upon the skills of the operator of the printer to eliminate the effects of variables which occur among color negatives and color papers.
Under present technology, most photograph negatives fall into an average range which the sensor electronics of an automatic printer can adequately handle by reference to the standard or master negative. The average range is basically a color and light balance setting which is a compromise between extremes of darkness, brightness and multiple basic colors. This compromise, since it is within a mean range, will produce many acceptable prints from color negatives. The range of acceptable negatives depends upon the quality of the operator's skills and time which he devotes to balancing the colors on a given print.
When defective photographs occur under present technology, it is generally for one or two reasons. The first and most common reason is density failure. When this occurs, the color prints are too dark or too light which results in loss of detail in the resulting image on the print.
The second common area of failure is subject failure. When this occurs, the print is too red, too blue, too green, too cyan, too magenta or too yellow. For example, blue tinted skin tones in a resulting photographic print are the result of subject failure.
Density failure occurs when the negative to be printed has excessive light or dark areas in relation to the colors of the standard negative. Subject failure occurs when the negative to be printed has an excessive area of one color in relation to the standard negative.
Because of the foregoing drawbacks in connection with conventional printers, a need exists for improvements in the making of color photographic prints so as to reduce and substantially eliminate problems due to density failure and subject failure as described above. The present invention satisfies this need as hereinafter described.